1. Field of the Invention
The present invention relates to a semiconductor manufacturing process, and particularly to a method of making a semiconductor device with a metal silicide layer on the top of a gate and a pair of source/drain and the semiconductor device.
2. Description of the Prior Art
As integration of elements in integrated circuits (IC) increases, line widths and geometries for semiconductor devices are reduced. Accordingly, resistance of a gate and source/drain regions of a MOS transistor made by conventional techniques is relatively high. To reduce resistance, a metal silicide layer is formed on the gate and the source/drain regions by a self-aligned silicide (salicide) process. Nickel silicide is commonly used as a salicide material. However, as the MOS is further scaled down, NiSi/Si interface Schottky barrier height (SBH) is becoming more and more important.
Furthermore, because the NiSi layer is formed by two thermal treatments, the temperature employed in the later one is higher. Under such temperature, silicon tends to aggregate to grow crystals, such that the NiSi layer is formed un-continuously and resistance is increased to affect the electric properties.
Therefore, there is still a need for a novel method of making a semiconductor device to overcome the aforesaid disadvantages to obtain a semiconductor device having a Si/NiSi interface with a low SBH and a low resistance.